The Astrophysical Research Consortium (ARC) 3.5m telescope is the largest aperture telescope on site. It was constructed in the early 90s by the ARC consortium, and is financially supported by thecurrent ARC partners. The optical design of the telescope is a Ritchey-Chretien, and provides an F/10 beam. It is an alt-az telescope, and instruments can be mounted at either of the two Nasmyth focii or at several other ports on the telescope, each of which can be accessed by rotating the tertiary mirror.
The telescope hosts a suite of optical and near-IR instruments and was designed to allow for rapid instrument changes, which can be accomplished by a single person during the night. The ARC 3.5m also pioneered the use of remote observing; most of the observations are made remotely by scientists, while an on-site observing specialist is present to monitor conditions and provide support.
Observing time is split between the member institutions according to their financial contributions, and is allocated internally at each institution. To improve efficiency, the telescope is scheduled in half-night blocks (sometimes even shorter).
The current Director is Dr. Nancy Chanover (NMSU).
